The genus Brucella is a member of family Brucellaceae and includes ten species which are small, non-motile, non-sporing, aerobic, gram-negative intracellular coccobacilli. They are catalase, oxidase and urea positive bacteria. Members of the genus can grow on enriched media like blood agar or chocolate agar. Identification in species level can be done by agglutination with monospecific serum, cultivating the strains in the presence of dyes and/or with PCR methods. Antigenic structure of the Brucella is composed of surface, intracellular, and in vivo antigens. Thanks to various virulence factors that act as metabolic regulators, Brucella strains can protect themselves from immune system of the host, adapt easily to different environmental conditions, and multiply intracellular. Classification, epidemiological features, isolation and identification, antigenic structure and virulence factors of Brucella species along with the discussion of very few patents associated with Brucellosis have been reviewed in this paper.